diff --git a/groups_cli_test.go b/groups_cli_test.go
index 3eb721f5..1e176909 100644
--- a/groups_cli_test.go
+++ b/groups_cli_test.go
@@ -17,6 +17,7 @@ func groupsHome(t *testing.T) {
 	t.Setenv("USERPROFILE", os.Getenv("HOME"))
 	t.Setenv("XDG_CONFIG_HOME", t.TempDir())
 	t.Setenv("XDG_CACHE_HOME", t.TempDir())
+	t.Setenv("DSH_HOME", "") // a dsh profile is found through it, not through HOME
 	for _, p := range []provider.Provider{
 		{ID: "a", Name: "A", Key: "ka", Models: []string{"m", "only-a", "claude-opus-5-5"}, Chat: "http://127.0.0.1:1/v1"},
 		{ID: "b", Name: "B", Key: "kb", Models: []string{"vendor/m", "gpt-5.5"}, Chat: "http://127.0.0.1:1/v1"},
diff --git a/internal/agent/main_test.go b/internal/agent/main_test.go
new file mode 100644
index 00000000..71caa581
--- /dev/null
+++ b/internal/agent/main_test.go
@@ -0,0 +1,38 @@
+package agent
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+// TestMain gives the package a home of its own. A home an agent is found
+// through can sit outside HOME — DSH_HOME does — and the package's tests
+// sandbox HOME alone: left as the developer has it, a test that picks a model
+// writes it into the real ~/.dsh/profiles, and dsh then refuses every turn
+// with a model its provider does not list. internal/gateway, internal/provider
+// and internal/usage isolate themselves the same way.
+func TestMain(m *testing.M) {
+	home, _ := os.MkdirTemp("", "magpie-agent-test-")
+	for k, v := range map[string]string{
+		"HOME": home, "USERPROFILE": home,
+		"XDG_CONFIG_HOME": filepath.Join(home, ".config"),
+		"XDG_CACHE_HOME":  filepath.Join(home, ".cache"),
+		"XDG_DATA_HOME":   filepath.Join(home, ".local", "share"),
+		"APPDATA":         filepath.Join(home, "AppData", "Roaming"),
+		"LOCALAPPDATA":    filepath.Join(home, "AppData", "Local"),
+	} {
+		os.Setenv(k, v)
+	}
+	for _, k := range []string{
+		"CLAUDE_CONFIG_DIR", "CODEX_HOME", "COPILOT_HOME", "GROK_HOME", "DSH_HOME",
+		"PI_CODING_AGENT_DIR", "PI_CODING_AGENT_SESSION_DIR", "PI_CONFIG_DIR",
+		"OMP_PROFILE", "PI_PROFILE", "OPENCODE_DB", "CLINE_DIR", "CLINE_DATA_DIR",
+		"CLINE_SESSION_DATA_DIR", "WORKBUDDY_CONFIG_DIR",
+	} {
+		os.Unsetenv(k)
+	}
+	code := m.Run()
+	os.RemoveAll(home)
+	os.Exit(code)
+}
diff --git a/internal/gateway/main_test.go b/internal/gateway/main_test.go
index 0e803306..ff0a2712 100644
--- a/internal/gateway/main_test.go
+++ b/internal/gateway/main_test.go
@@ -37,7 +37,7 @@ func isolatedTests(m *testing.M) (int, error) {
 			return 1, err
 		}
 	}
-	for _, name := range []string{"CLAUDE_CONFIG_DIR", "CODEX_HOME", "COPILOT_HOME", "GROK_HOME"} {
+	for _, name := range []string{"CLAUDE_CONFIG_DIR", "CODEX_HOME", "COPILOT_HOME", "GROK_HOME", "DSH_HOME"} {
 		if err := os.Unsetenv(name); err != nil {
 			return 1, err
 		}
diff --git a/internal/profile/profile_test.go b/internal/profile/profile_test.go
index e18f31be..0d8e63cc 100644
--- a/internal/profile/profile_test.go
+++ b/internal/profile/profile_test.go
@@ -19,7 +19,7 @@ func sandbox(t *testing.T) string {
 	t.Setenv("USERPROFILE", h)
 	t.Setenv("XDG_CONFIG_HOME", filepath.Join(h, ".config"))
 	t.Setenv("PATH", "")
-	for _, k := range []string{"CLAUDE_CONFIG_DIR", "CODEX_HOME", "PI_CODING_AGENT_DIR", "OMO_CODING_AGENT_DIR", "SENPI_CODING_AGENT_DIR", "COPILOT_HOME", "APPDATA", "LOCALAPPDATA"} {
+	for _, k := range []string{"CLAUDE_CONFIG_DIR", "CODEX_HOME", "PI_CODING_AGENT_DIR", "OMO_CODING_AGENT_DIR", "SENPI_CODING_AGENT_DIR", "COPILOT_HOME", "APPDATA", "LOCALAPPDATA", "DSH_HOME"} {
 		t.Setenv(k, "")
 	}
 	for _, f := range []string{".claude/settings.json", ".codex/config.toml"} {
diff --git a/internal/sessions/calls_test.go b/internal/sessions/calls_test.go
index 22747e4e..d5f30af8 100644
--- a/internal/sessions/calls_test.go
+++ b/internal/sessions/calls_test.go
@@ -22,6 +22,7 @@ func setupCalls(t *testing.T) callDirs {
 	t.Setenv("XDG_DATA_HOME", filepath.Join(dir, "data"))
 	t.Setenv("CLAUDE_CONFIG_DIR", d.claude)
 	t.Setenv("CODEX_HOME", d.codex)
+	t.Setenv("DSH_HOME", "")
 	t.Setenv("HOME", filepath.Join(dir, "home"))
 	t.Setenv("USERPROFILE", filepath.Join(dir, "home"))
 	callDesktopDirs = func() []string { return []string{d.desktop} }
diff --git a/internal/tui/tui_test.go b/internal/tui/tui_test.go
index 1bdeebe0..38ecb4c4 100644
--- a/internal/tui/tui_test.go
+++ b/internal/tui/tui_test.go
@@ -24,7 +24,7 @@ func home(t *testing.T) string {
 	t.Setenv("XDG_CACHE_HOME", filepath.Join(h, ".cache"))
 	t.Setenv("PATH", "")
 	t.Setenv("XDG_DATA_HOME", filepath.Join(h, ".local", "share"))
-	for _, k := range []string{"CLAUDE_CONFIG_DIR", "CODEX_HOME", "APPDATA", "VISUAL", "EDITOR", "OPENCODE_DB", "PI_CODING_AGENT_DIR", "OMO_CODING_AGENT_DIR", "SENPI_CODING_AGENT_DIR", "PI_CODING_AGENT_SESSION_DIR"} {
+	for _, k := range []string{"CLAUDE_CONFIG_DIR", "CODEX_HOME", "APPDATA", "VISUAL", "EDITOR", "OPENCODE_DB", "PI_CODING_AGENT_DIR", "OMO_CODING_AGENT_DIR", "SENPI_CODING_AGENT_DIR", "PI_CODING_AGENT_SESSION_DIR", "DSH_HOME"} {
 		t.Setenv(k, "")
 	}
 	for _, f := range []string{".claude/settings.json", ".codex/config.toml"} {
diff --git a/sessions_cli_test.go b/sessions_cli_test.go
index 5ac22957..2613da31 100644
--- a/sessions_cli_test.go
+++ b/sessions_cli_test.go
@@ -29,6 +29,7 @@ func sessionsHome(t *testing.T) time.Time {
 	t.Setenv("PI_CODING_AGENT_DIR", filepath.Join(h, ".pi", "agent"))
 	t.Setenv("OPENCODE_DB", "")
 	t.Setenv("PI_CODING_AGENT_SESSION_DIR", "")
+	t.Setenv("DSH_HOME", "")
 	for from, env := range map[string]string{"claude": "CLAUDE_CONFIG_DIR", "codex": "CODEX_HOME"} {
 		dir := filepath.Join(h, "."+from)
 		if err := os.CopyFS(dir, os.DirFS(filepath.Join("internal", "sessions", "testdata", from))); err != nil {